to volunteer. military doctors patched up his son who would say was wounded in iraq years ago, his wife urged him to go. >> she said you have to do it, something took care of your son, now you go take care of somebody else's. >> reporter: his daughter, also a doctor, says she is concerned about her dad's decision to put himself in harm's way for three years, but she is not surprised. >> this is not so much a sacrifice, but a duty he is willing to do. >> i am 35 years into treating civilians, now i am very honored to be able to serve the military and our wounded warriors. >> reporter: one man, extending his commitment to healing, all the way to a war zone. rehema ellis, nbc news, new york. >>> right now, thank you for joining us, i'm brian williams, we hope to see you later tonight for rock center, 10 eastern, 9 central time. and we hope to see you right back here tomorrow night. good evening.